The present invention relates to a method for determining the receiver of location information sent by an access network node. The invention further relates to a method for a control node and a method for an access network node for executing the invention, a mobile services switching centre and a GPRS support node adapted to executing said method and software adapted to control a control node and a software adapted to control an access network node in a way that the nodes execute the invented method.
Location services are defined for example in 3GPP (third Generation Partnership project) specifications TS22.071, version 3.2.0, published January 2000. In general, location services deliver a service that is related to the location of user equipment. To provide a location service, a service provider depends on the knowledge of the location of user equipment.
FIG. 1 depicts the architectures standardised in 3GPP TS 23.271, version 5.0.0, published October 2001. The architecture comprises two Gateway Mobile Location centres GMLC1, GMLC2, connected to core network nodes MSC, SGSN. One of the gateway mobile location centres GMLC1 is connected to an external location service client LCSC, to a home location server MSC or SGSN and a home subscriber server HLR or HSS. The other gateway mobile location centre GMLC2 is connected to an external public land mobile network PLMN. The control nodes MSC, SGSN are connected to the home location server HLR and a home subscriber server HSS, as well as to a radio access network UMTS Radio Access node SRNC. The radio access node is a radio network controller SRNC and is further connected to a node B and a further radio network controller RNC. The node B serves a user equipment UE.
The Gateway Mobile Location Centres GMLC1, GMLC2 contain functionality required to support location services. In one network, there may be more than one Gateway Mobile Location Centre.
The Gateway Mobile Location Centre GMLC1, GMLC2 is the first node an external location services in a mobile network. The Gateway Mobile Location Centre GMLC1, GMLC2 may request routing information from the home location register HLR or the home subscriber server HSS. After performing registration authorisation, it sends positioning requests to mobile services switching centre MSC or the serving GPRS (General Packet Radio Service) support node SGSN and receives final location estimates from the corresponding entity.
The home location register HLR and the home subscriber server HSS contain location services subscription data and routing information. For a roaming mobile subscriber, home location register/home subscriber server HLR/HSS may be in a different mobile network from the one he is currently roaming into. The location services subscription data are transferred from the home location register/home subscriber server HLR/HSS to the mobile services switching centre MSC or the serving GPRS support node SGSN during the location update procedure.
Location services subscription data include a privacy profile containing the privacy classes for which location of the target subscriber is permitted. Each privacy class is treated as a distinct supplementary service with its own supplementary service code.
The mobile services switching centre MSC and the serving GPRS support node SGSN contain the functionality responsible for the user's location services subscription and privacy. The location services functions of mobile services switching centre MSC and the serving GPRS support node SGSN are also related to charging and billing, location services co-ordination of all location requests, authorisation and authentication of the positioning requests received from the Gateway Mobile Location Centre GMLC1, GMLC2.
The serving radio network controller SRNC provides, among the others, the serving mobile location client functionality that means it is the node in which the user equipment location information is calculated.
The location services system provides the opportunity of requesting the location of the mobile user terminals from an external location services client (Mobile Terminating Location Request=MT-LR), the location from the terminal itself (Mobile Originating Location Request=MO-LR) and the auto-induced location from the network (Network Induced Location Request=NI-LR).
The node B, the radio network controller SRNC, RNC and the user equipment UE are not explained in more detail.
FIG. 2 gives an example of a circuit switched, mobile terminating, location request.
In this figure the access network nodes node B, serving radio network controller SRNC and radio network controller RNC are combined in the radio access network RAN. An external entity EE sends a location request LRQ to a mobile service switching centre MSC to gain location information of a user equipment UE. The mobile services switching centre MSC executes paging, authentication and ciphering with the user equipment UE. These steps may be redundant in the case of a busy user equipment.
In the depicted case of UMTS (Universal Mobile Telecommunications System) access, the Location Request is sent from the mobile services switching centre MSC to the radio access network RAN by means of RANAP (Radio Access Network Application Protocol) LOCATION_REPORTING_CONTROL message LRC. The steps performed to execute a calculation of a position of the user equipment UE depend on proprietary positioning methods. The result of the calculations is received in RANAP LOCATION_REPORT message LR. The location request result is sent from the mobile services switching centre MSC to the external entity EE in a LOCATION_REQUEST_RESULT message LRR.
LOCATION_REPORTING_CONTROL and LOCATION_REPORT RANAP messages are used for both Location Services and other mobile services switching centre MSC or serving GPRS support node functions SGSN, not related to Positioning, asking to report upon change of Service Area. If positioning is requested, the serving radio access controller shall report on a per request base, if reporting upon change of Service Area is requested, the serving radio access controller shall report whenever the user equipment UE moves between Service Areas.
It is a shortcoming of the system as described in 3GPP TS 23.271, version 5.0.0 and in 3GPP TS 25.413, version 4.2.0, that it is not possible to distinguish a LOCATION_REPORT message received as a result of a Service Area change from the same message received as an answer on an external location request. In the case that a service area change is reported by a LOCATION_REPORT message while a LOCATION_REPORT message is expected as an answer to a LOCATION_REPORTING_CONTROL message that demands an immediate response, there is no mechanism to distinguish between the respective LOCATION_REPORT messages. It is object of the invention to introduce a system that can distinguish between LOCATION_REPORT messages, sent as an answer on different events.